This invention relates to methods of ordering small objects, such as semiconductor chips, in arrays suitable for visual inspection.
Typically, most visual inspection systems, such as those used in robotics, have trouble in distinguishing objects that overlap. Therefore, a method of ordering chips for this specific use without damaging the chips is necessary. In the past, the task of ordering and testing semiconductor chips was done by a human operator, who separated and examined each small chip using a camel hair brush, tweezers, a needle-like vacuum pickup, and a lot of patient effort. If time were not a parameter of concern in the development of products which incorporate these chips, then the human operator would sufficiently provide this service (assuming no significant damage where done by the tweezers and the pickup). However, time is an important factor, and other methods of ordering, such as vibrating the chips on a surface to produce a nonoverlapping pattern, are currently being used and investigated. Vibrating the chips in some cases is harmful because it scratches the chips.
It is therefore an object of this invention to provide a means for producing a suitable array of objects which may be inspected effectively by a visual inspection system.